Canada's Prime Minister Justin Trudeau has confirmed the beheading of a Canadian taken hostage in the southern Philippines last year and held for a $21 million ransom by al-Qaida-linked militants.

Trudeau, speaking Monday, voiced outrage at the killing of retiree John Ridsdel, calling it an "unnecessary death ... an act of cold-blooded murder."

FILE - This undated handout photo released by Eastern Mindanao Command on Sept. 22, 2015, shows Canadian tourist John Ridsdel, 68, who was kidnapped by gunmen Sept. 21 on Samal island.

Ridsdel was one of two Canadian nationals seized along with a Norwegian resort manager in September at a marina on the southern island of Mindanao. Weeks later, Abu Sayyaf gunmen released a video of their hostages, demanding $21 million each for their release.

The captives were seen on camera begging for their lives. The most recent video showed Ridsdel saying he would be killed April 25 if the ransom were not paid.

Trudeau's comments came hours after police on Jolo island — an Abu Sayyaf stronghold — said two unidentified people on a motorbike dropped a severed head wrapped in plastic near a government facility.

There was no word on the fate of the remaining hostages.

On April 8, government forces seeking to free hostages engaged Abu Sayyaf militants in an hours-long firefight in nearby Basilan province. A military statement said 18 soldiers were killed and more than 50 others wounded in the battle, along with at least five militants.

There was no word at that time about the hostages, and it was not clear whether Ridsdel was among them.

Abu Sayyaf — a splinter group of the now-disbanded Moro Islamic Front — was founded in 1991 with funding from al-Qaida. It has been designated a terrorist group by the United Nations, Australia, Canada, Indonesia, Malaysia and the Philippines. The United Arab Emirates, Britain and the United States also have classified Abu Sayyaf as a terrorist organization.